**TLDR:** Move the changelog, currently called ["hotfixes to the stable
channel"](https://github.com/flutter/flutter/blob/master/docs/releases/Hotfixes-to-the-Stable-Channel.md),
to the root directory of Flutter/Flutter and rename it to CHANGELOG.md
before the Q3 release cutoff.

This PR accomplishes the following:
1. Renames 'Hotfixes-to-the-stable-channel' to CHANGELOG.md
2. Moves CHANGELOG.md to Flutter/Flutter root.
3. Update references to 'Hotfixes-to-the-stable-channel' to
CHANGELOG.md.

---

#### Background
Flutter has historically kept documentation on wiki pages in the Flutter
repository. Recently, we executed a large-scale migration of our wiki
into a `docs` folder within flutter/flutter.

#### Proposal
I propose relocating the current changelog, which is called ["hotfixes
to the stable
channel"](https://github.com/flutter/flutter/blob/master/docs/releases/Hotfixes-to-the-Stable-Channel.md),
to the root directory of the Flutter/Flutter repository and renaming it
to CHANGELOG.md. This change aims to improve the visibility,
accessibility, and consistency of our documentation processes.

#### Benefits
1. **Unify Dart and Flutter Processes:** This move aligns Flutter’s
changelog management with Dart's practices. As the release manager for
both Dart and Flutter, this unification will streamline the processes
and ensure consistency across projects.

#### Timeline
I would like this proposal **approved or denied before the Q3 release
cutoff** so it may be available within the stable branch.

---

> [!NOTE] 
> This proposal aims to improve our workflow and documentation
standards. I am open to feedback and further discussion on how we can
best implement this change.